While much of the B-21’s stealth-related characteristics and performance metrics remain classified, analysts expect the aircraft to be the world’s stealthiest upon delivery to the US Air Force.
The Northrop Grumman B-21 Raider, currently in development under top-secret conditions, is expected to take the mantle of the world’s stealthiest aircraft. The B-21 is explicitly designed to infiltrate across enemy airspace stealthily, evade the world’s most advanced air defense systems, conduct precision air strikes, and return home unscathed.
The B-21’s stealth performance is an aggregate of several different technologies, including aircraft design, stealth material used, and advanced onboard sensors. All the aforementioned factors will be incorporated into the design of the world’s stealthiest aircraft.
Perhaps the most crucial factor in the B-21’s stealth performance is its flying wing design airframe. In a flying wing design, an aircraft’s fuselage and wings are blended fully, and vertical and horizontal stabilizers are removed altogether. This design results in a shape that is less likely to reflect radar energy when compared to traditional aircraft designs.
The B-21 Raider’s flying wing design is nothing new, as the Northrop Grumman B-2 Spirit, the aircraft that the B-21 will eventually replace, also features a flying wing configuration. However, the B-21’s shape is more advanced, with blended surfaces and no sharp edges or right angles. The result will be a radar cross section (RCS) substantially lower than the B-2’s own.
However, the B-21’s peculiar shape is only the foundation of its stealth technology. Slathered atop the shape are the world’s most advanced radar-absorbing materials (RAM). RAM is integral to an aircraft’s stealth performance, thanks to its ability to either absorb or scatter radar waves, rather than reflect them like the surfaces found on traditional aircraft.
Radar waves are not the only aircraft emissions that can trigger detection. The B-2’s designers also took measures to reduce the aircraft’s infrared (IR) signature, which is especially important when avoiding the missiles and sensors that rely solely on heat for guidance/detection. To reduce the B-21’s IR signature, the engines were embedded within the aircraft’s fuselage, which serves to reduce the B-21’s exhaust heat. Furthermore, the B-21 features shaped exhaust nozzles, which serve to cool the exhaust before it emits from the aircraft. This clever innovation should reduce the likelihood of a missile lock from heat-seeking systems, thereby enhancing the B-21’s survivability in hostile territory.
Taking the B-21’s stealth performance to new heights is the management of communications-related emissions. To avoid detection of the electronic nature, the B-21’s communications, radar, and sensor systems were designed for Low Probability of Intercept (LPI) operation. LPI means that the B-21 can send and receive data in narrow beams that are exceedingly difficult for the enemy to detect.
While much of the B-21’s stealth-related characteristics and performance metrics remain classified, analysts expect the aircraft to be the world’s stealthiest upon delivery to the US Air Force.
The B-21 Raider’s Specifications
- Year Introduced: 2023 (first flight; not yet in operational service as of 2025)
- Number Built: 6 (test and initial production aircraft, as of 2025)
- Length: ~69 ft (21 m)
- Height: ~20 ft (6.1 m)
- Wingspan: ~140 ft (43 m)
- Weight:
- Empty: Classified (estimated ~60,000–70,000 lbs)
- Standard conditions: Classified
- Maximum takeoff weight: Estimated ~140,000 lbs (official figure not released)
- Engines: Two Pratt & Whitney turbofan engines (exact model classified; believed to be derivatives of the F135 or a new variant)
- Top Speed: High subsonic (exact figure classified)
- Range: ~6,000 mi (9,600 km) unrefueled (officially “intercontinental”)
- Service Ceiling: Classified (estimated ~50,000 ft)
- Loadout:
- Internal bays only (stealth optimized)
- Conventional or nuclear ordnance
- Precision-guided munitions (JDAM, JASSM, etc.)
- Nuclear gravity bombs (B61-12, B83, etc.)
- Potential future hypersonic/stand-off weapons
- Aircrew: 2 (pilot + mission commander; capable of uncrewed/remote operations in the future)
About the Author: Harrison Kass
Harrison Kass is a senior defense and national security writer at The National Interest. Kass is an attorney and former political candidate who joined the US Air Force as a pilot trainee before being medically discharged. He focuses on military strategy, aerospace, and global security affairs. He holds a JD from the University of Oregon and a master’s in Global Journalism and International Relations from NYU.
Image: Wikimedia Commons.
